Well perforating assembly



Oct. 22, 1963 B. M. CALDWELL ETAL 3,107,512

WELL PERFORATING ASSEMBLY Original Filed March '7, 1956 4 Sheets-Sheet 1 INVENTOR5 644% M. CflDWELL #472010 0. QWf/V wr United States Patent 3,107,612 WELL PERFQRATENG ASSEMBLY Blake M. Caldwell and Harrold 1). Gwen, Fort Worth, Tern, assignors to Halliburton Company, Duncan, Okla, a corporation of Delaware Continuation of application Ser. No. 570,003, Mar. 7, 1956. This application Feb. 7, 1961, Ser. No. 87,715 9 Claims. (Cl. 102-20) This invention relates to a well perforating assembly and more particularly to an assembly adapted to be lowered through a well tubing and fired after its emergence.

This application is a continuation of our copending application Serial No. 570,003, filed March 7, 19 56, for Well Perforating Assembly, now abandoned.

In the completion of wells such as oil and gas wells drilled by the rotary method it has been the practice to perforate the casing adjacent the producing formation to admit oil and gas from the formation to the well. Such perforating has been done before the well was capped'and while the drilling mud was in the casing. More recently however, the practice has been adopted of perforating after the tubing has been inserted into the well, the well head equipment aflixed and the drilling mud removed. This latter method requires lowering through the relatively small tubing the perforating assembly to the vicinity of the producing formation and then perforating.

Various perforating assemblies have been developed for this type of perforating. A particularly effective type maintains the perforating elements in vertical alignment during the lowering through the tubing and permitting the elements to pivot upon emergence from the tubing to a horizontal firing position such as disclosed in W. H. Thompson et a1. Patent No. 2,543,814, issued March 6, 1951 on Means and Method of Tilting Explosive Charges. A further improvement on this type of assem bly provides for the retraction of the assembly after emergence from the tubing is described in an application for United States Letters Patent filed February 19, 1954 by Blake M. Caldwell and I oe P. Wier, Serial No. 411,349, entitled Tilting Charge Well Perforating Assembly, now Patent No. 3,067,678. Still a further improvement upon such an apparatus resides in controlling the pivoting of the perforating elements from the ground surface, also in guarding against unexpected firing of the elements as described in an application for United States Letters Patent filed October 8, 1954 by Blake M. Caldwell and Harrold D. Owen, Serial No. 461,236 entitled Well Perforating Assembly, now Patent No. 3,067,679.

In such an apparatus there is provided a firing head having an elongated carrier suspended therefrom. A plurality of pivotally mounted shaped charges are mounted in the carrier which are biased towards the horizontal but which are locked in a vertical position during descent of the assembly into the well. Means operable from the surface are provided for releasing the shaped charges after the assembly has emerged from the tubing to permit same to pivot to the firing position, and the firing circuit in such an apparatus is not completed until the shaped charges have so pivoted. It will be noted, however, that in the above apparatus the shaped charges pivoted alternately in opposite directions. Where deep penetration is desired, and particularly within casing of relatively small diameters, this fact presents considerable disadvantage, for in such an assembly the charge must of necessity be relatively small.

On the other hand, given an apparatus wherein all the charges extend, in firing position, in the same direction, it is apparent that larger charges may be used. It is thus an object of this invention to provide a perforating assem- 3-,lll7,6l2 Patented Oct. 22, 1963 bly wherein all of the shaped charges extend, when in firing position, in the same direction.

It is still a further object of this invention to provide greater firing power in a perforating assembly utilizing pivoting shaped charges.

It is still a further object of this invention to provide means for controlling the direction of firing of a perforating assembly.

It is still a further object of this invention to provide a perforating assembly having improved breakup characteristics upon firing of the shaped charges.

Other objects and advantages will be readily apparent from the following description.

In the drawings:

FIGURE 1 is an elevational view of a perforating assembly illustrating one embodiment of this invention.

FIGURE 2 is a side elevation of the embodiment of FIGURE 1. 7

FIGURE 3 is a view similar to FIGURE 2 of the assembly in a well tubing with a portion of the carrier and other parts broken away.

FIGURE 4 is a view similar to FIGURE 3, illustrating the pivoting of the charges after emergence from the tubing.

FIGURE 5 is a fragmentary side elevation illustrating pivoting of the shaped charges.

FIGURES 6 is a view taken along line '6-6 of FIG- URE 5.

FIGURE 7 is a perspective 'view of the shaped charge locking element.

FIGURE 8 is a view similar to FIGURE 3 of a further embodiment of this invention.

FIGURE 9 is a view similar to FIGURE 4 of the second embodiment of the invention.

FIGURE 10 is a fragmentary side elevation with parts broken away illustrating pivoting of the shaped charges.

FIGURE 11 is a View taken along line 11-11 of FIG- URE 10.

FIGURE 12 is a perspective view of the locking element.

The invention generally comprises a plurality of pivotally mounted shaped charges in a carrier, which are spring urged to all pivot in the same direction wherein means are provided for locking the charges in axial alignment with the carrier during descent into the well and wherein means are provided to release the charges for pivotal movement to firing position after the zone to be perforated has been reached.

The perforating assembly comprises a firing head it supported from the surface by a conductor cable (not shown). The assembly may be lowered through the tubing 14- of the Well Within the casing 16. Suspended from the firing head is an elongated carrier 18 which carries a plurality of pivotally mounted shaped charges, the charges being each mounted in the carrier by means of opposed screws 22 which are screwed into each shaped charge as at 24. The carrier has a plurality of axially aligned windows 26 formed therein, one for each shaped charge, which windows are sufiiciently large to permit pivoting of the shaped charge from an axially aligned position to a position normal to the axis of the carrier 18. Behind each window 26 is a second opening 28 which among other things contributes to the breaking up of the carrier upon firing of the shaped charges 20.

A firing fuse 30 is threaded through the carrier 18 which fuse passes adjacent and rearwardly of each shaped charge, a pair of raised ridges 32 being formed on each shaped charge which confine the firing fuse therebetween and in contact with the shaped charge both before and after pivoting of the charges. The shaped charges 20 are each urged to pivot to the horizontal or firing position 3 by means of a spring 34, one extremity of which is secured to one of the ridges 32 by passing through a suitable opening therethrough and the other extremity is secured to the carrier 18 by passing through a suitable opening therethrough.

During descent of the assembly through the tubing 1% each of the shaped charges 20 is interlocked in an axially aligned position with respect to the carrier 18. For this purpose a shaft 36 is secured in the carrier by screws 38 between adjacent shaped charges. Mounted upon shaft 36 is a pair of opposed ratchets 40* and 42 which are spaced from one another, each spaced charge being provided with a detent 44 formed on one of the ridges 32 at its upper extremity adapted to engage a ratchet 40. Similarly each shaped charge has a detent 46 at its lower extremity adapted to engage an opposite ratchet 42. Thus when all the shaped charges are axially aligned the detents 44 and 46 engage opposite ratchets of the pair above and below each shaped charge. Since the springs 34 all urge their respective shaped charges to pivot in the same direction the lower detent 46 in each instance tends to rotate each shaft 36 while the upper detent 44 prevents such rotation. Thus as long as the lower detent 46 of the bottom shaped charge is restrained each of the charges is locked in axial alignment with carrier 18.

A detonating cap 48 is supported in the lower extremity of carrier 18 which engages the detent 46 of the lowest shaped charge restraining pivoting thereof and locking all of the shaped charges in the axially aligned position as seen in FIGURE 3. When an electrical circuit is closed at the surface of the well the cap-48 is detonated through wire 50. This permits a spring 34 to pivot the lowest shaped charge to the horizontal or firing position. This pivoting of the lowest shaped charge moves its upper detent 44 out of engagement with its ratchet 4t} releasing same permitting pivoting of the next successive shaped charge and so on until each has reached the horizontal or firing position.

In place of the top shaped charge an arm 52 may be substituted which is provided at its lower extremity with a detent 54 to engage ratchet 42 on the upper shaft 36. This arm 52 upon pivoting arms the perforating assembly by completing the firing circuit. A plunger 56- is pivotally mounted upon arm 52 and at its upper extremity carries suitable means for closing switch 58 to arm the assembly. A more detailed description of this assembly may be found in Caldwell et al. application Serial No. 461,236, now Patent No. 3,067,679, referred to above. In the event the arm 52 fails to pivot a predetermined amount because of encountering an obstruction in the well i the assembly will not be armed.

When the arming process is completed the shaped charges may be fired throufl fuse 3% from the surface of the well. If for some reason it is desirable not to fire the perforating assembly and to withdraw same it is readily apparent that as each shaped charge engages the lower extremity of tubing 14 it is cammed to its axially aligned position with its detent 46 engaging its ratchet 42 and is locked when the detent -44 of the shaped charge immediately below engages its ratchet 40. Thus it is only necessary to grasp the last shaped charge as it emerges from the well to prevent pivoting of the charges and arming of the perforating assembly.

In FIGURES 8 through 12 a different embodiment of this invention is illustrated wherein like parts are given the same numerical designation with the addition of the exponent a. It is readily apparent that the difference between this embodiment and the one previously described lies in the elimination of ratchets 4t and 42 and substitution of the locking plate 6d. The shaft 36a is provided with an intermediate flattened portion to which is affixed the said plate 6%. The locking plate 60 is urged by a spring 62 to rotate in a direction opposite to the direction of rotation of the shaped charges which spring 62 has one extremity anchored in carrier 18a and the other in locking plate 60.

The detent 46:: on the lower extremity of a shaped charge engages locking plate 5% at its upper edge as best seen in FIGURE 10, while the upper detent 44a of the next lower shaped charge engages the lower edge of locking plate 64). In this manner the shaped charges are 10c ed in axial alignment during descent down the tubing 14-. The charges are released in the same manner as in the previously described embodiment by the firing of blasting cap 48a which frees detent 46a of the lowest shaped charge 204: and permits spring 34a to pivot same to the horizontal or firing position as seen in FIGURE 9 and in phantom in FIGURE 10. The pivoting or" this charge disengages its detent 44a from contacting locking plate 6% permitting rotation thereof to release the shaped charge immediately above and so on until each charge reaches the firing position. It will be noted that in the event of withdrawal prior to firing, as previously described, the detent 46a on the lower extremity of each shaped charge clears the locking plate as same is held by spring 62. The upper detent 441: on the next lower shaped charge, however, engages the locking plate upon pivoting of said charge and pivots the locking plate back to the locking position.

Thus in each embodiment a perforating assembly is provided wherein the shaped charges are maintained through suitable locking mechanisms in axial alignment in the carrier. When desired the blasting cap is set off freeing the lower shaped charge which pivots under urging of its spring, freeing the charge inimediately above which process continues until all the charges have pivoted to the firing position and are all aimed in the same direction. After all of the charges are facing the desired direction the firing circuit is armed and the charges may be tired from the well surface. If, however, it is desired to withdraw the assembly before firing it is withdrawn pivoting each charge to the axially aligned position where they are maintained by the locking means.

While what hereinbefore has been described are the preferred embodiments of this invention it is readily apparent that alterations and modifications can be resorted to without departing from the scope of this invention and such alterations and modifications are intended to be included within the appended claims.

We claim:

1. A perforating assembly comprising: an elongated carrier; means for lowering said carrier into a well;- V

shaped charges pivotally mounted in axial disposition in said carrier; springs in said carrier separately urging said charges to all pivot in the same direction from such axial disposition; shaped charge interlocking elements ro-' tatably mounted in said carrier between adjacent shaped charges, an extremity of each said adjacent shaped charge releasably engaging an interlocking element on opposite sides of the axis of rotation of the element; and means for releasably engaging the lowermost extremity of the lowermost shaped charge thereby restraining said shaped charges in axial disposition with respect to said carrier( 2. A perforating assembly comprising: an elongated carrier; means for lowering said carrier into a well; shaped charges pivotally mounted in axial disposition in said carrier; springs in said carrier separately urging said charges to all pivot in the same direction from such axial disposition; a locking plate rotatably mounted within said carrier between adjacent shaped charges; and detents on each said adjacent shaped charge for releasably engaging the locking plate on opposite sides of the axis of rotation of the locking plate.

3. A perforating assembly comprising: an elongated carrier; means for lowering said carrier into a well; shaped charges pivotally mounted in axial disposition in said carrier; springs in said carrier separately urging said charges to all pivot in the same direction from such axialdisposition; a locking plate rotatably mounted within saidcarrier between adjacent shaped charges; detents on each said adjacent shaped charge for releasably engaging the locking plate on opposite sides of the axis of rotation of the locking plate; and spring means in said carrier urging said locking plate to rotate in the opposite direction from the direction of pivoting of said shaped charges.

4. A perforating assembly comprising: an elongated carrier; means for lowering said carrier into a well; shaped charges pivotally mounted in axial disposition in said carrier; springs in said carrier separately urging said charges to all pivot in the same direction from such axial disposition; an interlocking member rotatably mounted within said carrier between adjacent shaped charges, said interlocking member carrying a pair of opposed ratchet means thereon; and detents one on each said adjacent shaped charge for releasably engaging the opposed ratchet means on the interlocking member.

5. A perforating assembly comprising: an elongated carrier; means for lowering said carrier into a well; shaped charges pivotally mounted in axial disposition in said carrier; springs in said carrier separately urging said charges to all pivot in the same direction from such axial disposition; a locking member rotatably mounted within said carrier between adjacent shaped charges; a pair of opposed ratchets on each locking member; each shaped charge having a ratchet engaging detent on each extremity thereof releasably engaging said opposed ratchets.

6. A perforating assembly comprising: an elongated carrier; means for lowering said carrier into a Well; shaped charges pivotally mounted in axial disposition in said carrier; springs in said carrier separately urging said charges to all pivot in the same direction from such axial disposition; shaped charge locking members rotatably mounted within said carrier between adjacent shaped charges; a pair of opposed ratchets on each locking member, each shaped charge having a ratchet engaging detent on each extremity thereof for releasably engaging opposed ratchets of the locking member above and below each shaped charge.

7. A perforating assembly comprising: an elongated carrier; means for lowering said carrier into a well; a plurality of shaped charges mounted in axial alignment in said carrier on parallel, transverse pivot axes; re silient means acting between said charges and said carrier urging saidcharges all to pivot in the same direction from such axial alignment; interlocking elements rotatably mounted in said carrier between adjacent shaped charges, each' interlocking element having a first detent means engaging a first shaped charge adjacent one side of said element to restrain pivotal movement of said first shaped charge when the interlocking element is stationary and to release said first shaped charge for pivotal movement upon rotation of said element, and a second detent means engaged by a second shaped charge adjacent the other side of said element to restrain rotation of said element, said second detent being released by said second shaped charge upon pivotal movement thereof to release said interlocking element for rotation; and means for releasably holding in axial alignment the terminal shaped charge that restrains rotation of an adjacent interlocking clement, thereby restraining all of said shaped charges in said axial alignment.

8. A perforating assembly as defined in claim 7 wherein each interlocking element comprises a locking plate having a face terminating in edges disposed on opposite sides of the axis of rotation of said interlocking plate, said face providing said first detent means adjacent one of said edges and said second detent means adjacent the other of said edges.

9. A perforating assembly as defined in claim 7 wherein each interlocking element comprises a pair of ratchet wheels rotatable as a unit, the teeth of the ratchet wheels facing in opposite directions, a tooth of one wheel providing said first detent means and a tooth of the other wheel providing said second detent means.

References Cited inlthe file of this patent UNITED STATES PATENTS 2,543,814 Thompson et a1. Mar. 6, 1951 2,639,770 Huber .May 26, 1953 2,644,519 Kanady July 7, 1953 2,664,156 Allen Dec. 29, 1953 2,664,157 Abendroth Dec. 29, 1953 2,664,158 McKean Dec. 29, 1953 FOREIGN PATENTS 1,029,798 France Mar. 11, 1953 

7. A PRFORATING ASSEMBLY COMPRISING: AN ELONGATED CARRIER; MEANS FOR LOWERING SAID CARRIER INTO A WELL; A PLURALITY OF SHAPED CHARGES MOUNTED IN AXIAL ALIGNMENT IN SAID CARRIER ON PARALLEL, TRANSVERSE PIVOT AXES; RESILIENT MEANS ACTING BETWEEN SAID CHARGES AND SAID CARRIER URGING SAID CHARGES ALL TO PIVOT IN THE SAME DIRECTION FROM SUCH AXIAL ALIGNMENT; INTERLOCKING ELEMENT ROTATABLY MOUNTED IN SAID CARRIED BETWEEN ADJACENT SHAPED CHARGES, EACH INTERLOCKING ELEMENT HAVING A FIRST DETENT MEANS ENGAGING A FIRST SHAPED CHARGE ADJACENT ONE SIDE OF SAID ELEMENT TO RESTRAIN PIVOTAL MOVEMENT OF SAID FIRST SHAPED CHARGE WHEN THE INTERLOCKING ELEMENT IS STATIONARY AND TO RELEASE SAID FIRST SHAPED CHARGE FOR PIVOTAL MOVEMENT UPON ROTATION OF SAID ELEMENT, AND A SECOND DETENT MEANS ENGAGED BY A SECOND SHAPED CHARGE ADJACENT THE OTHER SIDE OF SAID ELEMENT TO RESTRAIN ROTATION OF SAID ELEMENT, SAID SECOND DETENT BEING RELEASED BY SAID SECOND SHAPED CHARGE UPON PIVOTAL MOVEMENT THEREOF TO RELEASE SAID INTERLOCKING ELEMENT FOR ROTATION; AND MEANS FOR RELEASABLY HOLDING IN AXIAL ALIGNMENT THE TERMINAL SHAPED CHARGE THAT RESTRAINS ROTATION OF AN ADJACENT INTERLOCKING ELEMENT, THEREBY RESTRAINING ALL OF SAID SHAPED CHARGES IN SAID AXIAL ALIGNMENT. 